Effects of Salicylic Acid on some Growth and Physiological Characteristics of Lettuce (Lactuca sativa L.) under Cadmium Stress Conditions

Lettuce (Lactuca sativa L.) is considered as the most cultivated and consumed leafy vegetable all over the world. In Erbil Governorate, most farmers used sewage water to irrigate lettuce, which caused health risks especially heavy metal pollutants including cadmium. This research was applied as a factorial experiment to investigate the effects of foliar spraying of salicylic acid (SA) (0,0.5,1, 1.5 or 2mM) followed by spraying cadmium chloride (Cd) (0, 1, 2, or 4mM) on the growth, and some physiological and biochemical characteristics of this plant. Results show that most vegetative growth characteristics responded inversely to increasing SA concentrations, whereas the response of root performance improved with using SA application. A low concentration of Cd (1mM) improved root and shoot performance, whereas increasing the concentration to 4 mM decreased these characteristics significantly compared to no Cd added plants, except for the percent of shoot dry matter. Most of photosynthetic pigments decreased significantly by foliar spraying with SA and Cd. Applications of SA increased catalase enzyme activity significantly compared to no SA treated plants. Cadmium foliar application increased peroxidase enzyme activity, ascorbic acid, proline, and percent of total carbohydrate content and decreased catalase enzyme activity and the percent of infection with watery soft rot significantly compared to no Cd treated plants. It is concluded that lettuce tolerance to cadmium stress was increased by pretreatment foliar application of SA

STUDYING THE EFFECT OF CATIONIC STARCH- ANIONIC NANOSILICA SYSTEM ON RETENTION AND DRAINAGE

Nanoparticles are widely used in the papermaking industry as retention/ drainage aids, usually in conjunction with a high mass cationic polyelectrolyte such as cationic starch. However, little convincing knowledge of their role and mechanism in the wet-end system is yet found. This work focused on the role of nanosilica on papermaking wet end system in response to some processing parameters (drainage, retention, and electrostatic force of the whole system). The observations indicated that the nanosilica performance is defined by interactions of nanosilica with the complex aqueous environment of wet end system. The interaction mechanism seems to rely on introduction of nanoparticles into a cationic starch-fines-fibers network, converting the fiber mat on the forming wire into a porous structure that is responsive to retention and drainage

Effect of He-Ne Laser on Blood Serum Testosterone and Testicular Tissue in Adult Male Rat

The current study was conducted to examine the effect of He-Ne laser therapy on the blood serum testosterone level and testicular tissue in adult male rats. Thirty five Albino Western adult male rats aged 3-4 months and weighing approximately 250-300 g were used and divided in to three groups. The  testicular tissue of rats in the first treatment was exposed to a dose of irradiation 1.02 j/cm2 (40 second) once daily for three successively days, while second treatment was exposed to a dose of irradiation 2.03 j/cm2 (80 second) once daily for three successive date, while the third group remained without any treatments (control).  The results showed that the process of irradiation adversely affected on the level of blood serum testosterone in the first and second treatment compared to the normal level in the control group. The histological examination in treatment one showed  low reduction in numbers of sertoli , leydig  and spermatid cells   at day one, while in day two  showed medium reduction in numbers of sertoli , leydig  and spermatid cells,and high reduction in numbers of sertoli , leydig  and spermatid cells  in day three of irradiation. In treatment two, the results showed   medium reduction in numbers of sertoli , leydig  and spermatid cells at day one, while in day two  showed high reduction in numbers of sertoli , leydig  and spermatid cells and very high reduction in numbers of sertoli , leydig  and spermatid cells in day three of irradiation . In conclusion the current study revealed that steers factor cause reduction in numbers of sertoli , leydig  and spermatid cells  lead to  low fertility rate within  increasing of duration and repetition of irradiation

Fundamentals of strength loss in recycled paper

Considerable work has been devoted to the upgrading of recycled chemical (low yield) pulp fibers during the past decade. There is also disagreement on the effectiveness of an upgrading process regardless, whether of chemical or mechanical origin. One serious problem which restricts sustainable progress in the field of fine-paper recycling is the lack of knowledge of the mechanism by which recycling affects the texture and arrangement of the cell wall which ultimately causes inferior properties of the recycled fibers. The deteriorative effect of recycling on fine-paper manifested itself on the loss in potential bonding of recycled fibers. The loss in potential bonding of the recycled fibers translated into hornification (i.e., loss in fiber wet-flexibility) and/or surface deactivation by recycling. The susceptibility of the fibers for hornification rather than surface deactivation during recycling is substantiated with different techniques. It is concluded that the hornification is responsible for inferior properties of recycled fibers. More importantly, observations in the present work suggest that refining/beating does not develop any new surface area. The effect of refining is restricted to a reduction in the rigidity of the lamellae by mechanical fatigue and subsequently, increased swelling and plasticization of the fiber wall. Thus, drying of never-dried fibers (unbeaten or beaten) from water pulls the lamellae toward each other by surface tension forces and binds the lamellae rich in surface by crystallization forces. These forces lead to an increase in the crystallization of the cell wall provided that the condition required for crystallization, is met by the molecular orientation in the cell wall. When these fibers are re-wetted again, the delamination does not reverse completely, and the lamellae remain partially closed. This results in increased rigidity of unraveled lamellae and restricts the internal surfaces of fibers to access by water. The concomitant result is restricted swelling and thus, loss in wet-plasticity of the fibers on recycling. Most of this change takes place in the first cycle. Repeated recycling deteriorates further the wet-plasticity of the fibers. Based on these findings a model is proposed which explains the mechanism by which hornification develops in the fiber wall during recycling. The proposed model also provides new information on the effects of fiber beating or refining.Forestry, Faculty ofGraduat